Russia’s conflict with Ukraine stems in part from the Kremlin’s concern that Kyiv is drawing too close to institutions such as the European Union and NATO. Throughout his campaign, President Donald Trump called into question the usefulness of today’s NATO and spoke of building a better relationship with Moscow. Advocating change, he has shaken trans-Atlantic bonds and arguably seen some results. Would the president be prepared to go further and suggest ending NATO expansion while seeking a new security architecture that might accommodate and reduce the risk of conflict with Russia? What would be the benefits and costs of such an approach?